A lot of the non-bot content seems to be fairly local stuff: hit pieces against local Democrats or praise for local Republicans. The underlying issues are similar, but the articles themselves don't seem to lend themselves to being aggregated in that manner. Plus, it doesn't seem like a good idea to try to present a false consensus when all the sites you're linking to look like the same site.
And I highly doubt that they're focusing on email as the means of reaching new users. This clickbait is meant to spread via Facebook posts.
> hit pieces against local Democrats or praise for local Republicans.
This suggests another possible reason. Those behind them have found that if the 'fake' site appears to be 'local' enough, it will be seen as more reliable and/or it is more likely to get "liked" (given your "spread via Facebook posts"). Possibly their A/B testing has shown that fake 'local' stuff gets more spreading on FB?
I don't think that's "another" possible reason so much as you're closing in on the original accusation. The reddit group linked upthread refers users to this article explaining these sites: https://www.nytimes.com/2019/10/31/upshot/fake-local-news.ht...
All you're missing out on at this point is the obvious partisan motivation.
And I highly doubt that they're focusing on email as the means of reaching new users. This clickbait is meant to spread via Facebook posts.